Alloy steel



Patented Mar. 22, 1927.

UNITED STATES WILLIAM HERBERT KEEN, OF ALBANY, NEW YORK- ALLOY STEEL.

R Drawing.

The present invention relates to alloy steels of the t pe commonly known as h g speed steel an hasfor an object to rov1de an improved steel especially adapta 10 for 5 use in makin tools and the like. The invention has a o for an object to provide an improved tool.

I have discovered that a steel of the type commonly known as high speed st eel but having much better cutting qualities and greater durability can be produced by 1ncreasing the content of both the carbon and the vanadium beyond the proportions usually considered feasible or desirable in steels of this character.

The nature and objects of the 1nvent1on will be better understood .from a description of an illustrative embodiment thereof.

The allo steel to be described for the i purposes o illustrating the invention, may

contain in general the usual elements found in high speed alloy steels, but with the vanadlum and carbon increased beyond the usual proportions. as The steel may contain for example The increase of the proportion of vanadium beyond 1% when accompanied by an increase in the proportion of carbon to between 0.75% and 0.85% or more, efiects an increase in the toughness of the steel while the hardening roperty remains unimpaired. The increase of the proportion of vanadium beyond 3 to 5% is probably notgenerally commercially desirable because of the increased cost of the steel, a higher percentage however, would not be detrimental to quality.

The carbon can be increased to at least 1.15 or 1.20% but to increase the carbon unduly tends to make the roduct brittle and difficult to work. For t is reason and for other practical reasons, I prefer orditially beyond .90%. If, however, the proportion of vanadium is to be substantially increased, it may then be desirable to also increase the proportion of carbon even bea yond the preferred limit stated.

Variations may be made from the abov narily not to increase the carbon substan- Application filed May 10, 1924. Serial No. 712,454.

formula as by substituting e uivalent elements or by departing'from t e limits indicated as desirable without sacrificing the advantages of the increase of carbon and vanadium. For example, the tungsten can be reduced somewhat or may be increased as for example to 23%. The cobalt can be increased very substantially, as for example, to 9 or 10%. creased as to 5.50% or decreased to less than 3%.

The analysis of illustrative satisfactory steels made in accordance with the invention showed the following compositions:

. Per cent. Per cent. Carbon .85 1.16 Vanadium 3.25 3.53 Tungsten 18.00 23.19 Chromium 4.00 4.14 Cobalt None. None. Manganese 0.25 0.33 Sulphur 0.020 0.015 Phosphorus 0.015 0.010 Silicon 0.15 0.12

An alloy such as either of those the analys1s of which is given above, is forgeable and may be used for example in making of lathe tools, milling cutters hobs and the like with excellent results. uch tools have great hardness and toughness and are capable of retaining'their cutting edges when working at a red heat. They have far greater endurance than tools made of steels having the usual composition and require less frequent grinding. The tools may be hardened by the usual methods employed for the hardening of high speed tool steels. For example, tools made of the steel the analysis of which is specifically given hereinabove, may be hardened by heating to a temperature of 2200 to 2300 F. and chilling elther in. oil or air blast followed by drawing temper to about 1200 F. The stated tem eratures do not define exact limits as will be readily understood. The 2300 heat is best accomplished by rapid increase of tem erature from a lower preheat to cherry red about 1400 F.).

The foregoing description is to be construed as il ustrative merely and not as defining the limits of the invention.

Claims:

1. An air-hardening forgeable high speed steel containing approximately 3% vana- The chromium may be inair-hardening. It is suitable for use in manufacture of so-called high speed tools and dium, 0.85% or more carbon, ap roximately 18% tungsten and approximate y 4% chromium.

2. A forgeable high speed steel containing 2.5% to 5% vanadium, 0.8% to 1.2% carbon, to 19% tungsten, 2.5% to 5% chromium.

3. A forgeable hi h speed steel comprising 3% to 5% vana ium, 0.8% to 1.2% carbon, approximately 15% to 19% tungsten, approximately 3% to 5% chromium, and approximately 1% to 5% cobalt.

4. An air-hardeningiorgeable high speed steel comprising vanadium in a proportion approximately 3% to 5%, carbon in a proportion approximating .75% to 1.2%, tungsten in a proportion approximating 15% to 23% and chromium in a proportion approximating 2.5% to 5.5%, the content of vanadium and carbon being such as to provide an air-hardening forgeable steel having the customary red hardness of high speed steel.

5. A forgeable high speed steel containing approximately 2.5% to 5% vanadium, and approximately 0.8% to 1.2% carbon, said steel being capable of being hardened, the

content of vanadium and carbon being such as to provide an air-hardenin forgeable steel having the customary red hardness of high speed steel.

6. A forged steel cutting tool characterized by great hardness and toughness and capable of retaining its cutting edges when working at a red heat, the steel whereof contains approximately 3% vanadium and a proximately 0.85% carbon, the steel of said tool being in a hardened condition.

7. A forged steel cutting tool characterized by great hardness and toughness and capable of retaining its cutting edges when working at a red heat, the steel whereof contains 2.5% to 5% vanadium, 0.8% to 1.2% carbon, 15% to 19% tungsten and 3% to 5% chromium, the steel of said tool being in a hardened condition as is reduced by heating to a temperature of a out 2200 to 2300 F. and chilling followed by tempering to about 1200 F.

In testimony whereof, I have signed my name to this specification this 8th day of May 1924.

WILLIAM H. KEEN. 

